How to use finite difference to find slope for a function?

I have a function F(x)=x^2 + x - 10, how can I creat code for forward, back ward and central finite difference approximation of the slope ? I don't know where can I start.

[dpb]

Start buy defining the function...

fnF=@(x)x.^2 + x - 10;

Then you have to evaluate the function over whatever range of x you're interested in before doing differences of any sort.

[wenchong chen]

I only got how to find slope for a point, how to find slop for (-1 to 1) in finite difference approximation?

Answer 1

[Shubham Khatri]

Hello,

I have used forward finite difference approximation to design the following code for the purpose.

h=0.1; % step's size
N=10; % number of steps
y(1)=-10;
for n=1:20
    y(n+1)= y(n)+h*(4*y(n) + 41)^(0.5);
end
x = -1:0.1:1.1;
plot(x,y);

Hope it helps